U.S. patent number 9,681,416 [Application Number 15/269,713] was granted by the patent office on 2017-06-13 for method for transmitting and receiving paging information in a broadband wireless access system.
This patent grant is currently assigned to LG Electronics Inc.. The grantee listed for this patent is LG ELECTRONICS INC.. Invention is credited to Han Gyu Cho, Jin Soo Choi, Jae Hoon Chung, Jong Young Han, Eun Jong Lee, Hyung Ho Park, Kyu Jin Park, Doo Hyun Sung.
United States Patent |
9,681,416 |
Lee , et al. |
June 13, 2017 |
Method for transmitting and receiving paging information in a
broadband wireless access system
Abstract
A method for efficiently transmitting and receiving a paging
message and system information from and in a mobile station of a
broadband wireless access system is disclosed. A method for
receiving a paging message in a mobile station comprises receiving
paging information from a serving base station, the paging
information including paging sub group identifier (paging sub group
ID) indicating a paging sub group to which the mobile station
belongs; and receiving the paging message for a predetermined
paging interval of the paging sub group, wherein the paging sub
group is determined separately from a paging group and a
geographical location determining the paging group, and is
maintained while the mobile station is being operated in an idle
mode.
Inventors: |
Lee; Eun Jong (Anyang-si,
KR), Sung; Doo Hyun (Anyang-si, KR), Choi;
Jin Soo (Anyang-si, KR), Cho; Han Gyu (Anyang-si,
KR), Han; Jong Young (Anyang-si, KR), Park;
Kyu Jin (Anyang-si, KR), Park; Hyung Ho
(Anyang-si, KR), Chung; Jae Hoon (Anyang-si,
KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
LG ELECTRONICS INC. |
Seoul |
N/A |
KR |
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Assignee: |
LG Electronics Inc. (Seoul,
KR)
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Family
ID: |
41398667 |
Appl.
No.: |
15/269,713 |
Filed: |
September 19, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170013593 A1 |
Jan 12, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14167913 |
Jan 29, 2014 |
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12865833 |
Feb 25, 2014 |
8660064 |
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PCT/KR2009/002945 |
Jun 3, 2009 |
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61061106 |
Jun 12, 2008 |
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61058553 |
Jun 3, 2008 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L
5/0007 (20130101); H04W 68/02 (20130101); H04W
72/042 (20130101); H04W 88/08 (20130101) |
Current International
Class: |
H04W
68/02 (20090101); H04L 5/00 (20060101); H04W
72/04 (20090101); H04W 88/08 (20090101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1875559 |
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Dec 2006 |
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CN |
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1973570 |
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May 2007 |
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CN |
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101043706 |
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Sep 2007 |
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CN |
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10-2006-0043526 |
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May 2006 |
|
KR |
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10-0661569 |
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Dec 2006 |
|
KR |
|
Primary Examiner: Lo; Diane
Attorney, Agent or Firm: Dentons US LLP
Parent Case Text
This application is a continuation application of U.S. application
Ser. No. 14/167,913 filed Jan. 29, 2014, which is a continuation
application of U.S. patent application Ser. No. 12/865,833 filed
Nov. 19, 2010, now U.S. Pat. No. 8,660,064, which is a National
Stage entry of International Application No. PCT/KR2009/002945
filed Jun. 3, 2009, which claims priority to U.S. Provisional
Application Nos. 61/058,553 filed Jun. 3, 2008 and 61/061,106 filed
on Jun. 12, 2008, all of which are incorporated by reference for
all purposes as if fully set forth herein.
Claims
The invention claimed is:
1. A method of receiving a message by a terminal, the method
comprising: receiving indication information included in a
signaling part of a frame via a broadcast channel, wherein the
indication information indicates whether the message is included in
a first part of the frame other than the signaling part of the
frame, wherein when the indication information is set to a first
value, the message is included in the first part of the frame and
when the indication information is set to a second value, the
message is not included in the first part of the frame; when the
indication information is set to the first value, obtaining the
message in the first part of the frame according to the indication
information, wherein the message includes update information
indicating whether broadcast information is changed; and acquiring
the changed broadcast information when the update information
indicates that the broadcast information is changed, wherein both
the indication information and the message are included in the
frame, wherein the signaling part is located in front of the first
part in the frame, wherein the first part of the frame is
transmitted in a subframe unit, and wherein interval information
which is set in the subframe unit is included in the signaling part
of the frame.
2. The method of claim 1, wherein the broadcast information is
received periodically.
3. The method of claim 1, wherein a location where the message in
the frame is received is defined in accordance with a previously
determined rule.
Description
TECHNICAL FIELD
The present invention relates to a broadband wireless access
system, and more particularly to, a method for transmitting and
receiving paging information efficiently.
BACKGROUND ART
In the following description, a generally used paging group and an
idle mode of a terminal are schematically explained.
FIG. 1 is a diagram illustrating a paging group in a general IEEE
802.16 system.
Referring to FIG. 1, a plurality of base stations (BS) supporting
an idle mode belong to a paging group to construct a paging
area.
In this case, the paging group indicates a logical group. If there
is a traffic that targets a mobile station (MS), the object of the
paging group is to provide a neighbor range area that can be paged
in downlink (DL). And, the paging group should meet the condition
to be large enough for a specific terminal to exist for most of
time within a same paging group and the condition to be small
enough for a paging load to maintain a proper level.
FIG. 1 shows four paging groups defined on multiple base stations
located at hexagonal lattices. One base station is able to be
included in one or more paging groups. The paging group is defined
by a management system. And, a paging group is able to use a paging
group-action backbone network message. Moreover, a list of terminal
in idle mode is managed using a paging-announce message
corresponding to one of backbone network messages and initial
paging of all base stations belonging to a paging group can be
managed.
Idle mode indicates an operation of supporting a terminal to
periodically receive a downlink (DL) broadcast traffic transmission
without registering at a specific base station when the terminal is
moving in a wireless link environment constructed with multiple
base stations.
Idle mode is able to give the benefit to a terminal by eliminating
a handover-related activation requirement and general operation
requirements. Idle mode is able to save power and operational
resources used by a terminal in a manner of put limitation on a
terminal action to be scanned in a discrete cycle.
Idle mode provides a simple and proper method of informing a
terminal for a downlink traffic in pending and is able to give the
benefit to a network and a base station by removing a wireless
interface and a network handover (HO) traffic from an inactive
terminal.
Hereinafter, an example of an operation procedure of a mobile
station entering an idle mode in a general IEEE 802.16 system will
be described with reference to FIG. 2. Referring to FIG. 2, a
mobile station can transmit a deregistration request (DREG-REQ)
message to a serving base station to enter an idle mode from a
normal mode (S201).
The serving base station which has received the DREG-REQ message
can transmit and receive information of the mobile station and the
serving base station to and from a paging controller. Namely, the
serving base station can notify the paging controller of mobile
station identifier (MSID) and serving base station identifier
(BSID). Also, the paging controller can notify the serving base
station of paging group identifier (PG ID) or paging controller
identifier (PC ID). The paging group identifier or the paging
controller identifier can be used to transmit and receive a paging
message.
Subsequently, the serving base station can transmit a
deregistration command (DREG-CMD) message to the mobile station.
The serving base station can transmit the deregistration command
(MOB_DREG-CMD) message to the mobile station in response to the
deregistration request message. The deregistration command message
can include paging information. At this time, the paging
information can include parameters such as paging cycle, paging
offset, and paging listening interval. The deregistration command
message can further include paging controller identifier and paging
group identifier (S203).
At this time, the paging information can be included in the
deregistration command message in a type of Table 7 below. This
information can be provided to the mobile station through a ranging
response (RNG-RSP) message in a location update procedure which
will be described later.
TABLE-US-00001 TABLE 1 Type Length Value Scope 134 7 Bits #0-15:
PAGING_CYCLE - cycle in which the paging RNG-RSPDREG- message is
transmitted within the paging group. Bits CMD #16-31: PAGING_OFFSET
- determines the frame within the cycle from which the paging
interval starts. Shall be smaller than PAGING_CYCLE value. Bits
#32-47: Paging-group-ID- ID of the paging group the MS is assigned
to. Bits #48-55: Paging Interval Length - Max duration in frames of
Paging Listening interval. Used in calculation of Paging listening
interval. value shall be between 1 and 5 frames (default = 2).
The parameters in Table 1 are user equipment-specific values, and
different paging cycles, paging offsets and paging listening
intervals can be allocated to the respective mobile stations. The
base station can identify a paging interval of each mobile station
through the parameters.
The mobile station which has received the DREG-CMD message from the
serving base station identifies that a request of entrance to an
idle mode is successfully accepted, and enters the idle mode. The
mobile station can receive a paging message based on paging
information received through the MOB_DREG-CMD message.
Namely, the mobile station can monitor a radio channel to identify
the presence of a paging message transferred thereto for a paging
listening interval. The mobile station is operated in a sleep mode
(or the radio channel is turned off) for the other interval to
reduce power consumption (S204).
A call or external packet can be transmitted to the paging
controller (S205).
In this case, the paging controller can perform a paging procedure
of the mobile station. At this time, the paging controller can
transmit a paging announcement message to all base stations within
the paging group (S206).
All the base stations within the paging group, which have received
the paging announcement message, can broadcast a MOB_PAG-ADV
message to all mobile stations managed by the base stations. At
this time, the paging message can include parameters of Table 2
(S207).
TABLE-US-00002 TABLE 2 Syntax Size (bit) Notes for (i = 0; i <
Num_Paging_Group_IDs; -- -- i++) { Paging Group ID -- 16 } -- --
Num_MACs -- Number of MS MAC addresses For (j = 0; j < Num_MACs;
j++) { -- -- MS MAC Address hash 24 The hash is obtained by
computing a CRC24 on the MS 48-bit MAC address. The polynomial for
the calculation is 0x1864CFB Action Code 2 Paging action
instruction to MS 0b00 = No action required 0b01 = Perform ranging
to establish location and acknowledge message 0b10 = Enter network
0b11 = Reserved Reserved 6 -- } -- -- Padding variable Padding bits
to ensure octet aligned TLV Encoded Information variable
TLV-specific } --
The mobile station checks the MOB_PAG-ADV message. If the mobile
station is paged by the paging controller, the mobile station
enters a normal mode and is then able to perform communications
with the serving base station (S208, S209).
In a general communication system, mobile stations belonging to the
same paging group can have different paging intervals. These paging
intervals can be managed by the paging controller or the base
station. The paging intervals will be described with reference to
FIG. 3.
FIG. 3 is a diagram illustrating different paging intervals of two
different mobile stations, which belong to the same paging group in
a general communication system.
Referring to FIG. 3, it is assumed that two mobile stations MS1 and
MS2 exist in the same paging group. At this time, in the mobile
station MS1, the first frame of the paging cycle can be established
as a paging interval, and in the mobile station MS2, the fourth
frame of the same paging cycle can be established as a paging
interval.
Next, a procedure of updating system information in a mobile
station which is in an idle mode will be described.
The mobile station which is in the idle mode wakes up for only a
listening interval and then receives a paging message.
Subsequently, the mobile station takes a corresponding action in
accordance with an action code value. For example, if an action
code corresponding to the mobile station is `0`, the mobile station
does not take any action. If an action code corresponding to the
mobile station is `1`, the mobile station can perform ranging for
location update.
It is assumed that a downlink channel descriptor (DCD) message, an
uplink channel descriptor (UCD) message or neighboring cell
information transmitted from a preferred base station of the mobile
station which is in the idle mode is updated. At this time, in a
general wireless communication system, the preferred base station
can notify the mobile station of a frame where a message containing
the updated DCD/UCD or neighboring cell information is transmitted
by transmitting a broadcast control pointer information element
(Broadcast_Control_Pointer_IE) to the mobile station. Table 3
illustrates contents that can be included in the broadcast control
pointer information element.
TABLE-US-00003 TABLE 3 Syntax Size (bit) Notes
Broadcast_Control_Pointer_IE( -- -- ) { Extended DIUC 4
Broadcast_Control_Pointer_IE( ) = 0xA Length 4 Length in bytes
DCD_UCD Transmission 7 The most significant bits of the frame Frame
number's least 9 significant bits of the next DCD and/or UCD
transmission. Skip Broadcast_System_Update 1 -- If (Skip -- --
Broadcast_System_Update == 0) { Broadcast_System_Update_Type 1
Shows the type of Broadcast_System_Update0: For MOB_NBR-ADV Update
1: For Emergency Services Message
Broadcast_System_Update_Transmission _Frame 7 The least significant
bits of the frame number of the next Broadcast_System_Update
transmission. } -- -- } -- --
Referring to Table 3, the broadcast control pointer information
element can include information of a frame (DCD_UCD transmission
frame) where the DCD/UCD messages are transmitted, and a frame
(broadcast_system_update_transmission_frame) for update of
broadcast system information.
Unlike the mobile station which is in an active mode, the mobile
station which is in the idle mode can receive a message by waking
up for only a listening interval. Since the updated DCD or UCD
message has a relatively great transmission cycle (maximum ten
seconds), if the updated message is not transmitted within the
listening interval of each mobile station, each mobile station may
not receive the updated message. Such a case will be described with
reference to FIG. 4.
FIG. 4 is a diagram illustrating an operation procedure of updating
system information through a mobile station, which is in an idle
mode, in a general communication system.
Referring to (a) of FIG. 4, the mobile station can receive the
broadcast control pointer information element from the preferred
base station for only its listening interval. The mobile station
can wake up to receive the updated system information even if a
frame indicated by the broadcast control pointer information
element does not correspond to the listening interval of the mobile
station. The mobile station can again sleep until next listening
interval if the updated system information is successfully
received.
However, it may be assumed that the mobile station fails to receive
the updated system information from the frame indicated by the
broadcast control pointer information element as illustrated in (b)
of FIG. 4. At this time, the mobile station may have to receive
system information by waking up until next interval where system
information is transferred.
DISCLOSURE OF INVENTION
Technical Problem
In a general broadband wireless access system, a paging controller
that manages a paging procedure of a mobile station should report
paging information (paying cycle, paging offset, paging interval,
etc.) of a corresponding mobile station to a base station if the
mobile station is paged. This is because that the base station can
exactly transmit a paging message to the corresponding mobile
station only when knowing an interval where the mobile station
wakes up.
In the worst case, a base station may have to transmit the paging
message every frame in accordance with a distribution of paging
intervals of mobile stations which are in idle mode.
Furthermore, even though a mobile station which is in an idle mode
knows a frame where system information is transmitted by
successfully receiving a broadcast control pointer information
element (IE) from a preferred base station so as to update system
information, the mobile station may fail to receive the system
information.
Moreover, it is assumed that sub maps are multiplexed with one
cyclic redundancy check (CRC) in a general system (for example,
IEEE 802.16e system), like a downlink map or an uplink map
(DL/UL-MAP). In this case, the mobile station waking up from a
paging subframe should decode the whole sub maps. Also, if the sub
maps are transmitted through a separate CRC attachment in
accordance with connection identifier (CID) (for example, CRC or
CID masking), the mobile station performs blind decoding for all
sub maps through corresponding CID in a general system (for
example, long term evolution (LTE) system), thereby detecting
control signals transmitted thereto. In case of a general wireless
communication system, broadcast CID is used to transmit a paging
message. If the message is transmitted using broadcast CID, the
mobile stations which are in a normal mode as well as the mobile
stations which are in an idle mode may all receive the paging
message. If the mobile station which is in a normal mode receives a
paging message, it causes unnecessary power consumption of the
mobile station and increases decoding overhead of the mobile
station.
The present invention is devised to substantially obviate one or
more problems due to limitations and disadvantages of the related
art. An object of the present invention is to provide method for
efficiently updating system information in a mobile station which
is in an idle mode.
Another object of the present invention is to provide a method for
efficiently paging a mobile station.
Other object of the present invention is to provide an operation
method for efficiently saving the power of a mobile station.
It is to be understood that the technical problems to be achieved
by the present invention are not limited to the aforementioned
problems and other technical problems which are not mentioned will
be apparent from the following description to the person with an
ordinary skill in the art to which the present invention
pertains.
Technical Solution
In order to solve the above technical problems, the present
invention provides various methods for efficiently transmitting and
receiving a paging message.
In one aspect of the present invention, a method for receiving a
paging message in a mobile station comprises receiving paging
information from a serving base station, the paging information
including paging sub group identifier (paging_sub_group_ID)
indicating a paging sub group to which the mobile station belongs;
and receiving the paging message for a predetermined paging
interval of the paging sub group, wherein the paging sub group is
determined separately from a paging group and a geographical
location determining the paging group, and is maintained while the
mobile station is being operated in an idle mode.
At this time, the paging interval is established in a subframe
unit.
Also, the method further comprises receiving paging indication
information indicating whether a paging message of at least one
paging sub group is transmitted. In this case, the step of
receiving the paging message is performed when the paging
indication information indicates the paging sub group to which the
mobile station belongs.
Also, the paging indication information includes at least one of
bits indicating whether the paging message of at least one paging
sub group is transmitted, and if the paging indication information
is transmitted twice or more within the paging cycle, the paging
indication information is transmitted at different superframes.
Also, the paging indication information is transmitted at a first
subframe of a superframe where a paging cycle starts, through any
one of a superframe header (SFH), a broadcast channel (BCH)
included in the superframe header, a data region of the first
subframe, and a sub-packet of a secondary superframe header.
Also, the paging interval is a subframe after predetermined offset
established in accordance with the paging sub group from the
subframe from which the paging indication information is
transmitted.
Also, the bits respectively represent whether the paging message of
one paging sub group is transmitted, and if the paging indication
information includes bits of all paging sub groups belonging to a
predetermined paging group, the paging information is broadcasted
to the mobile station through the superframe header.
Also, the paging message further includes a system information
update indication (SIUI) field, the method further comprises
performing update of system information if the SIUI field indicates
update of the system information.
Also, the step of performing update of system information includes
acquiring system information by decoding a superframe header (SFH)
received after a superframe where the paging message including the
system information update indication field is transmitted.
Also, the paging message is transmitted to the mobile station
through a downlink resource indicated by predetermined paging
message control information included in a sub-map of a subframe
corresponding to the paging interval, the predetermined paging
message control information is CRC masked by predetermined paging
CID for a specific mobile station of an idle mode, and the mobile
station performs blind decoding for the predetermined paging
message control information using its paging CID.
Also, the predetermined paging message control information has a
size previously established in a previously established location of
the sub-map.
In another aspect of the present invention, a method for
transmitting a paging message from a base station to a mobile
station comprises receiving a deregistration request message from
the mobile station; transmitting a deregistration command message
including paging information to the mobile station, the paging
information including paging sub group identifier
(paging_sub_group_ID) indicating a paging sub group to which the
mobile station belongs; and transmitting a paging message to the
mobile station for a predetermined paging interval of the paging
sub group, wherein the paging sub group is established separately
from a paging group and a geographical location determining the
paging group, and is maintained while the mobile station is being
operated in an idle mode.
At this time, the paging interval is established in a subframe
unit.
Also, the method further comprises receiving a paging indication
message of the mobile station from a paging controller; and
transmitting paging indication information to the mobile station,
the paging indication information indicating whether a paging
message of a paging sub group to which the mobile station belongs
is transmitted.
Also, the paging indication information is transmitted from a first
subframe of a superframe where a paging cycle starts, through any
one of a superframe header (SFH), a broadcast channel (BCH)
included in the superframe header, a data region of the first
subframe, and a sub-packet of a secondary superframe header.
Also, the step of transmitting a paging message is performed at a
subframe after predetermined offset previously determined for a
paging sub group to which the mobile station belongs, from a
subframe where the paging indication information is
transmitted.
In other aspect of the present invention, a method for receiving a
paging message in a mobile station of an idle mode comprises
monitoring the paging message for a first paging cycle; and
increasing the first paging cycle by a predetermined value if the
paging message is not received for the first paging cycle.
At this time, the step of monitoring the paging message and the
step of increasing the first paging cycle are repeated as much as
the number of times, which is previously determined.
Also, the step of increasing the first paging cycle is performed
until the first paging cycle becomes equal to a maximum paging
cycle which is previously determined.
Advantageous Effects
According to the present invention, the following advantages can be
obtained.
First of all, the mobile station which is in the idle mode can
update system information more efficiently.
Second, it is possible to page the mobile station which is in the
idle mode, more efficiently.
Finally, the mobile station can be operated in the idle mode more
efficiently.
It is to be understood that the advantages that can be obtained by
the present invention are not limited to the aforementioned
advantages and other advantages which are not mentioned will be
apparent from the following description to the person with an
ordinary skill in the art to which the present invention
pertains.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a diagram illustrating a paging group in a general IEEE
802.16 system;
FIG. 2 is a diagram illustrating an example of an operation
procedure of a mobile station which enters an idle mode in a
general IEEE 802.16 system;
FIG. 3 is a diagram illustrating paging intervals of two different
mobile stations belonging to the same paging group in a general
communication system;
FIG. 4 is a diagram illustrating an operation procedure of updating
system information through a mobile station, which is in an idle
mode, in a general communication system;
FIG. 5 is a conceptional view of a paging group that can be used in
a general wireless communication system and a paging sub group that
can be used in the embodiments of the present invention;
FIG. 6 is a diagram illustrating a paging interval to which a
paging subframe that can be used in the embodiments of the present
invention is applied and an operation of a mobile station;
FIG. 7 is a diagram illustrating a paging subframe per paging sub
group according to one embodiment of the present invention;
FIG. 8 is a diagram illustrating an example of a method for
updating system information of a mobile station which is in an idle
mode in accordance with one embodiment of the present
invention;
FIG. 9 is a diagram illustrating a location where a paging channel
can be transmitted in accordance with another embodiment of the
present invention;
FIG. 10 is a diagram illustrating a paging interval when a paging
message is transmitted through a paging channel according to
another embodiment of the present invention.
FIG. 11 is a diagram illustrating a location where a paging
indication bit in accordance with another embodiment of the present
invention is transmitted.
FIG. 12 is a diagram illustrating a location where a paging message
is transmitted according to another embodiment of the present
invention.
FIG. 13 is a diagram illustrating an example of a location where a
paging message is transmitted if paging indication bits are
transmitted at different times per paging sub group in accordance
with another embodiment of the present invention.
FIG. 14 is a diagram illustrating an example of a location where a
paging message is transmitted if paging indication bits of a
plurality of paging sub groups are transmitted at the same time in
accordance with another embodiment of the present invention.
FIG. 15 is a diagram illustrating an example of a 1 bit paging
indication method in accordance with another embodiment of the
present invention.
FIG. 16 is a diagram illustrating a method for transmitting a
paging message using bitmap type paging indication in accordance
with another embodiment of the present invention.
FIG. 17 is a diagram illustrating an example that a paging
indication grouping method in accordance with another embodiment of
the present invention is used.
FIG. 18 is a diagram illustrating another example that paging
indication grouping method in accordance with another embodiment of
the present invention is used.
FIG. 19 is a diagram illustrating an example of a location where
control signaling for a paging message in accordance with another
embodiment of the present invention is transmitted.
FIG. 20 is a diagram illustrating an example that a paging cycle of
a mobile station is determined in a multi-level in accordance with
the further embodiment of the present invention.
MODE FOR THE INVENTION
The present invention relates a wireless access system.
Hereinafter, methods for paging a mobile station more efficiently
in accordance with the embodiments of the present invention will be
described.
The following embodiments are achieved by combination of structural
elements and features of the present invention in a predetermined
type. Each of the structural elements or features should be
considered selectively unless specified separately. Each of the
structural elements or features may be carried out without being
combined with other structural elements or features. Also, some
structural elements and/or features may be combined with one
another to constitute the embodiments of the present invention. The
order of operations described in the embodiments of the present
invention may be changed. Some structural elements or features of
one embodiment may be included in another embodiment, or may be
replaced with corresponding structural elements or features of
another embodiment.
In the description of drawings, procedures or steps that may make
the subject matter of the present invention obscure will be
omitted, and procedures or steps equivalent to the range that can
be understood by those skilled in the art will be omitted.
The embodiments of the present invention have been described based
on the data transmission and reception between a base station and a
mobile station. In this case, the base station means a terminal
node of a network, which performs direct communication with the
mobile station. A specific operation which is described as being
performed by the base station may be performed by an upper node of
the base station as the case may be.
In other words, it will be apparent that various operations
performed for communication with the mobile station in the network
which includes a plurality of network nodes along with the base
station may be performed by the base station or network nodes other
than the base station. The base station may be replaced with terms
such as a fixed station, Node B, eNode B (eNB), and access point.
Also, the mobile station may be replaced with terms such as a user
equipment (UE), a subscriber station (SS), a mobile subscriber
station (MSS), and a terminal.
Furthermore, a transmitter means a fixed and/or mobile node that
transmits data service or voice service, and a receiver means a
fixed and/or mobile node that receives data service or voice
service. Accordingly, in an uplink, the mobile station could be a
transmitter, and the base station could be a receiver. Likewise, in
a downlink, the mobile station could be a receiver, and the base
station could be a transmitter.
Meanwhile, in the present invention, examples of the mobile station
include a personal digital assistant (PDA), a cellular phone, a
personal communication service (PCS) phone, a global system for
mobile (GSM) phone, a wideband CDMA (WCDMA) phone, and a mobile
broadband system (MBS) phone. Also, examples of the mobile station
include a personal digital assistant (PDA), a hand-held PC, a
notebook PC, a smart phone, and a multi mode-multi band (MM-MB)
terminal.
In this case, the smart phone means a terminal having advantages of
a mobile communication terminal and a personal mobile terminal in
combination. Namely, the smart phone can mean a terminal that data
communication functions such as schedule management, facsimile
transmission and reception, and Internet access, which correspond
to functions of the personal mobile terminal, are added to the
mobile communication terminal. Also, the multi mode-multi band
terminal means a mobile terminal having a multi-modem chip to be
operated in a portable Internet system and other mobile
communication systems (for example, code division multiple access
(CDMA) 2000 system, WCDMA system, etc.).
The embodiments according to the present invention may be
implemented by various means, for example, hardware, firmware,
software, or their combination.
If the embodiment according to the present invention is implemented
by hardware, the method according to the embodiments of the present
invention may be implemented by one or more application specific
integrated circuits (ASICs), digital signal processors (DSPs),
digital signal processing devices (DSPDs), programmable logic
devices (PLDs), field programmable gate arrays (FPGAs), processors,
controllers, microcontrollers, microprocessors, etc.
If the embodiment according to the present invention is implemented
by firmware or software, the method according to the embodiments of
the present invention may be implemented by a type of a module, a
procedure, or a function, which performs functions or operations
described as above. A software code may be stored in a memory unit
and then may be driven by a processor. The memory unit may be
located inside or outside the processor to transmit and receive
data to and from the processor through various means which are well
known.
The embodiments of the present invention can be supported by
standard documents disclosed in at least one of wireless access
systems, i.e., IEEE 802 system, 3GPP system, 3GPP LTE system, and
3GPP2 system. Namely, among the embodiments of the present
invention, steps or parts which are not described to clarify
technical spirits of the present invention can be supported by the
above standard documents. Also, all terminologies disclosed herein
can be described by the above standard documents. Particularly, the
embodiments of the present invention can be supported by one or
more of standard documents of the IEEE 802.16 system, i.e.,
P802.16-2004, P802.16e-2005 and P802.16Rev2.
Hereinafter, the preferred embodiments according to the present
invention will be described in detail with reference to the
accompanying drawings. It is to be understood that the detailed
description which will be disclosed together with the accompanying
drawings is intended to describe exemplary embodiments of the
present invention and is not intended to describe unique
embodiments by which the present invention can be carried.
Furthermore, specific terminologies hereinafter described are
provided to assist understanding of the present invention, and
various modifications can be made in the specific terminologies
within the range that they do not depart from technical spirits of
the present invention.
The present invention suggests a paging sub group that can be
determined separately from a paging group classified by a
geographic location to perform efficient paging. The paging sub
group can also be MS-specifically determined (e.g., using MS
identifier).
FIG. 5 is a conceptional view of a paging group that can be used in
a general wireless communication system and a paging sub group that
can be used in the embodiments of the present invention.
Referring to FIG. 5, when a mobile station moves from its paging
group region (for example, P_G1) to another paging group region
(P_G2), the mobile station can perform location update. As a
result, a new paging group identifier (PGID) is given to the mobile
station, and the mobile station belongs to a new paging group.
However, since a paging sub group is determined separately from the
paging group defined in accordance with the geographic location,
the paging sub group can be maintained regardless of a location of
the mobile station. Accordingly, if paging intervals of all mobile
stations belonging to the same paging sub group are determined
equally, the mobile station can receive a paging message at the
same time of a paging cycle regardless of a change of the paging
group, which is caused by movement of the mobile station.
For example, it is assumed that three mobile stations MS1, MS3, and
MS5 are established to a paging sub group 1 as illustrated in FIG.
5. If the mobile station MS1 moves from the region P_G1 to the
region P_G2, the paging group of the mobile station MS1 can be
updated through a location update procedure. However, since the
paging sub group is not related with the geographic location, the
mobile station may continuously be maintained at the paging sub
group 1. Hereinafter, a number of the paging sub group can be used
as the same meaning of paging sub group ID. Namely, paging sub
group ID of the paging sub group 1 could be 1.
This paging sub group can be determined by mobile station ID (MSID)
without separate signaling between a base station the mobile
station. In this case, in order to determine the paging sub group,
the mobile station or the base station can identify a paging sub
group of a corresponding mobile station by using a method of the
following Math Figure 1. Paging Sub Group ID=MS_ID modulo N [Math
Figure 1]
In the Math Figure 1, `N` represents the number of paging sub
groups, and can be transferred to the mobile station through system
information.
Also, the paging sub group can be given to the mobile station by a
paging controller or the base station through a deregistration
command (DREG-CMD) message during idle mode entry or a ranging
response (RNG-RSP) message during location update. This will be
described with reference to Table 4.
Table 4 illustrates an example that paging sub group information is
included in the deregistration command message or the ranging
response message that can be used in the embodiments of the present
invention.
TABLE-US-00004 TABLE 4 Type Length Value Scope xxx x PAGING_CYCLE
RNG- PAGING_OFFSETPaging RSPDREG- Interval LengthPaging-group-ID
CMD Paging-sub-group-ID: mobile station is grouped once more in sub
group not geographical grouping.
Referring to Table 4, the base station can notify the mobile
station of the paging sub group in such a manner that a paging sub
group ID value is added to a type length value (TLV) indicating
paging information in the deregistration command message or the
ranging response message.
The present invention additionally suggests a paging subframe
together with the aforementioned paging subgroup. The paging
subframe means a subframe where the paging message is transmitted.
The paging subframe will be described with reference to FIG. 6.
FIG. 6 is a diagram illustrating a paging interval to which a
paging subframe that can be used in the embodiments of the present
invention is applied and an operation of a mobile station.
In a general wireless communication system, a paging message
monitoring interval unit of the mobile station is a frame. However,
if the paging subframe is applied as illustrated in FIG. 6, the
mobile station can monitor the paging message in a subframe unit.
Accordingly, the mobile station can save the power more
efficiently. To this end, the TLV indicating paging information in
the ranging response message or the deregistration command message
transmitted from the base station to the mobile station can be
modified as illustrated in Table 5.
TABLE-US-00005 TABLE 5 Type Length Value Scope xxx x PAGING_CYCLE
RNG-RSPDREG- PAGING_OFFSET: CMD determines the subframe within the
cycle in which the paging message is transmitted. Must be smaller
than PAGING_CYCLE.Paging Interval Length: Max duration in subframes
of paging interval. (default = 1)Paging- group-ID
Referring to Table 5, paging offset and paging interval length can
be established in a subframe unit.
According to the embodiments of the present invention, the mobile
stations belonging to the same paging sub group can have the same
paging interval regardless of the paging group. Namely, the mobile
stations belonging to different paging sub groups wake up at
different paging intervals and then identify the paging message
while the mobile stations belonging to the same paging sub group
wake up at the subframe of the same paging interval and then
identify the paging message.
Hereinafter, a method for efficiently transmitting a paging message
using the aforementioned paging sub group and paging subframe will
be described in more detail.
1. Pacing Scheme Using Arbitrary Paging Subframe
According to one embodiment of the present invention, a paging
message can be transmitted from a arbitrary subframe.
Generally, a listening interval (MS Listening Interval) of a mobile
station and a Paging Interval (BS paging interval) of a base
station can be defined in a frame unit through paging information
that can be transmitted to the mobile station through a
deregistration command message or a ranging response message.
However, in this embodiment, the mobile station can receive a
paging message by waking up at only a arbitrary subframe of a
corresponding frame. At this time, mobile stations belonging to the
same sub group can check for the paging message by waking up at the
same subframe. This will be described with reference to FIG. 7.
FIG. 7 is a diagram illustrating a paging subframe per paging sub
group according to one embodiment of the present invention.
In the following embodiments including the embodiment of FIG. 7, it
is assumed that all paging sub groups belong to one paging group.
It is also assumed that all mobile stations belonging to the same
paging group have the same paging cycle regardless of a paging
interval (paging subframe) that can be defined by the paging sub
group.
Referring to FIG. 7, mobile stations belonging to the paging sub
group 1 can receive the paging message by waking up at only a
arbitrary paging subframe of the first frame even though the first
frame of the paging cycle is defined as the paging interval. Also,
mobile stations belonging to the paging sub group 2 can receive the
paging message by waking up at only a arbitrary paging subframe of
the fourth frame even though the fourth frame of the paging cycle
is defined as the paging interval.
1-1. Method for Receiving a Paging Message from a Paging Subframe
of a Paging Sub Group
A mobile station woken up at a arbitrary paging subframe can
receive a paging message, and can decode the paging message to
identify whether the presence of its paging information. Mobile
stations belonging to the same paging sub group receive the paging
message from the same paging subframe.
For example, it is assumed that a mobile station MS1 belongs to a
paging sub group 1, and a paging subframe designated in the paging
sub group 1 is N. At this time, if there is no paging message
transmitted from the paging subframe of the MS1, i.e., subframe N,
it may mean that all mobile stations belonging to the paging sub
group 1 are not paged. In this case, all mobile stations belonging
to the paging sub group 1 can enter an idle mode again.
By contrast, if there is a paging message transmitted at the paging
subframe N, all mobile stations belonging to the paging sub group 1
can identify the presence of its paging action code by decoding the
paging message. The mobile station which is commanded to perform
network reentry in accordance with the paging action code can be
operated in a normal mode by waking up from the idle mode. The
mobile station which is commanded to perform location update can
enter the idle mode after performing location update. The mobile
station which has not received any command can enter the idle mode
until next paging subframe.
1-2. Method for Updating System Information of a Paging Sub
Group
If a paging message is transmitted from a arbitrary subframe, a
mobile station may have a difficulty to know the presence of system
information update at the time when the mobile station wakes up.
For this reason, according to the related art, the mobile station
has known a frame where updated system information is transmitted
using a broadcast control pointer information element (IE) which is
transmitted to the mobile station during a paging interval.
However, in an advanced system, for example, a system that
periodically transmits system information, like a wireless
communication system subject to the IEEE 802.16m standard, it is
not required to notify the mobile station of a location where
system information will be transmitted. In the current IEEE 802.16m
system, the base station can transmit a broadcast channel (BCH) per
20 ms in a fixed location of a superframe.
The BCH is divided into a primary BCH (PBCH) and a secondary BCH
(SBCH). The PBCH can transmit network common information while the
SBCH can transmit cell specific information. The base station can
transmit update information of each system information block
through the BCH, and can provide scheduling information so that the
mobile station receives updated broadcast information. In this
case, there may be provided a plurality of system information
blocks, and the system information blocks may be regarded as a
bundle of system information that can be transmitted at different
cycles in accordance with a procedure.
Accordingly, this embodiment suggests that a field indicating the
presence of system information update is added to a paging message,
instead of a broadcast control pointer information element
according to the related art, wherein the broadcast control pointer
information element indicates a location of a frame where system
information is transmitted. This field will be referred to as a
system information update indication (SIUI) field in the present
invention. An example of this system information update indication
field included in the paging message will be described with
reference to Table 6.
TABLE-US-00006 TABLE 6 Syntax Size (bit) Notes
MOB_PAG-ADV_Message_format -- -- ( ){ Management Message Type = 61
8 -- Num_Paging_Group_IDs 8 For(i=0; -- --
i<Num_Paging_Group_IDs; i++){ Paging Group ID 16 -- } -- --
System information update indication 1 Set to 1 if information
transmitted through BCH is changed. Num_MACs 8 Number of MS MAC
addresses For(j=0; j<Num_MACs; j++){ -- -- MS MAC Address hash
24 The hash is obtained by computing a CRC24 on the MS 48-bit MAC
address. The polynomial for the calculation is 0x1864CFB Action
Code 2 Paging action instruction to MS0b00 = No action required0b01
= Perform ranging to establish location and acknowledge message0b10
= Enter network0b11 = reserved Reserved 5 -- } -- -- Padding
Variable Padding bits to ensure octet aligned TLV Encoded
Information Variable TLV-specific }
Referring to Table 6, the SIUI field can be set to a size of 1 bit.
The mobile station which has received the paging message including
the SIUI field set to `1` can receive the BCH from a superframe
header (SFH) by waking up at the first subframe of next superframe
to receive system information regardless of the paging interval.
This will be described with reference to FIG. 8.
FIG. 8 is a diagram illustrating an example of a method for
updating system information of a mobile station which is in an idle
mode in accordance with one embodiment of the present
invention.
Referring to FIG. 8, it is assumed that two different paging sub
groups (paging sub group 1 and paging sub group 2) exist in the
same paging group. It is also assumed that a paging subframe of the
paging sub group 1 is a arbitrary subframe of the first frame of
the paging cycle, and a paging subframe of the paging sub group 2
is a arbitrary subframe of the fourth frame. At this time, the
paging message including the SIUI field set to `1` can be
transmitted at each paging subframe of the paging sub group 1 and
the paging sub group 2. As a result, all mobile stations belonging
to each paging sub group can update system information by waking up
at the first subframe of next superframe of a superframe where the
paging message is transmitted and receiving the BCH.
If the SIUI field of the paging message transmitted to the paging
subframe of each paging sub group is set to `0` all mobile stations
of each paging sub group can know that there is no update of system
information, and can continuously be operated in the idle mode.
Meanwhile, according to this embodiment, even though the mobile
station fails to decode the BCH, since the time when next BCH is
transmitted is always fixed, the mobile station does not need to
stay up. Namely, even the mobile station fails to decode the BCH,
the mobile station is operated in the idle mode and then again
wakes up after 20 ms to receive the BCH. Also, the mobile station
which has successfully decoded the BCH can wake up at a subframe
other than the paging subframe to receive updated system
information in accordance with information provided from the
BCH.
2. Paging Method Limiting Paging Subframe Using Subframe Including
BCH
In the current wireless communication system, for example, the
system subject to the IEEE 802.16m standard, one superframe has a
length of 20 ms, and each superframe which is transmitted includes
a superframe header (SFH). The superframe header includes a
synchronous channel (SCH) and a broadcast channel (BCH). The BCH is
a channel that transmits broadcast information, and can be divided
into a PBCH and a SBCH. System information is also broadcast
information, and can be transmitted to the mobile station through
the BCH. Accordingly, if a mobile station which is in an idle mode
wakes up at only a subframe where the BCH is transmitted, the
mobile station can be operated more efficiently.
2-1. Paging Channel of Subframe Including BCH
According to this embodiment, a method for transmitting a paging
message at an SFH or a subframe where the SFH is transmitted, to a
mobile station through a paging channel (PCH) that can include a
paging message will be described.
FIG. 9 is a diagram illustrating a location where a paging channel
can be transmitted in accordance with another embodiment of the
present invention.
The paging channel can be included in the SFH as illustrated in
FIG. 9(a) or the BCH as illustrated in FIG. 9(b). Also, the paging
channel may be included in a predetermined location within a
subframe where the SFH is transmitted, and may be transmitted to
one of sub-packets of a secondary superframe header (SSFH).
FIG. 10 is a diagram illustrating a paging interval when a paging
message is transmitted through a paging channel according to
another embodiment of the present invention.
It is assumed that two different paging sub groups (paging sub
group 1 and paging sub group 2) exist. As described above, it is
preferable that a paging subframe is differently established per
paging sub group, and may be a subframe where the BCH is
transmitted. Accordingly, the paging subframes can be established
as the first subframes of different superframes per paging sub
group.
For example, as illustrated in FIG. 10, in case of the paging sub
group 1, the paging subframe can be established as the first
subframe of the first superframe of the paging cycle. Also, in case
of the paging sub group 2, the paging subframe can be established
as the first subframe of the second superframe of the paging
cycle.
2-2. Transmission of Paging Indication Bit from Subframe Including
BCH
In another aspect of this embodiment, a paging indication (PI) bit
or field indicating whether the paging message is transmitted can
be only transmitted at the subframe where the BCH is transmitted,
and the paging message can be transmitted at another subframe. The
paging indication bit may have a length of 1 bit or multi-bits as
occasion demands. For example, when a plurality of paging sub
groups exist, one bit can be allocated to each paging sub group.
The mobile station can receive the paging message only if a paging
indication bit allocated to its paging sub group is set to `1`.
FIG. 11 is a diagram illustrating a location where a paging
indication bit in accordance with another embodiment of the present
invention is transmitted.
The paging indication bit may be included in the SFH as illustrated
in FIG. 11(a) or the BCH as illustrated in FIG. 11(b). Also, the
paging indication bit may be included in a predetermined location
within the subframe where the SFH is transmitted, as illustrated in
FIG. 11(c), or may be transmitted to one of sub-packets of a
secondary superframe header (SSFH).
Hereinafter, a location of a paging message that can be transmitted
as a paging indication bit is set to `1` and a method for notifying
a mobile station of the location of the paging message will be
described.
2-2-1. Method for Notifying a Location where a Paging Message is
Transmitted
If a paging indication bit of a paging sub group to which the
mobile station belongs is set to `1`, the mobile station should
know the time when the paging message is transmitted and/or a
location where the paging message is transmitted, so as to receive
the paging message. Also, the mobile station is operated in the
idle mode until it reaches the location where the paging message is
transmitted, whereby the power can be saved efficiently.
FIG. 12 is a diagram illustrating a location where a paging message
is transmitted according to another embodiment of the present
invention.
In a subframe including a superframe, it is assumed that a paging
indication bit of a specific paging sub group is set to `1` and is
located to any one of locations described with reference to FIG.
11. At this time, a paging message of the specific paging sub group
may be included in the same superframe as that where the paging
indication bit is transmitted as illustrated in FIG. 12, or may be
included in another superframe within the same paging cycle. This
will be described in more detail with reference to FIG. 13 and FIG.
14.
FIG. 13 is a diagram illustrating an example of a location where a
paging message is transmitted if paging indication bits are
transmitted at different times per paging sub group according to
another embodiment of the present invention.
Referring to FIG. 13, it is assumed that two different paging sub
groups (paging sub group 1 and paging sub group 2) exist and paging
indication bits of respective paging sub groups are respectively
transmitted through the first subframes of different superframes.
At this time, the paging message of each paging sub group is
transmitted after a predetermined time, for example, i(i.gtoreq.1)
subframes, from the subframe where the paging indication bit is
transmitted.
Next, a case where a plurality of paging sub groups exist and
paging indication bits of respective paging sub groups are
transmitted at the same time will be described.
The paging indication bits may have a bitmap type to simultaneously
notify the mobile stations of the respective paging sub groups
whether the paging message of each of the plurality of paging sub
groups is transmitted. For example, if the paging messages of the
paging sub group 1 and the paging sub group 2 are only transmitted,
the paging indication bits of the paging groups are arranged
starting from the most significant bit (MSB) of the bitmap in the
order from the first paging sub group to the last paging sub group,
thereby having a type of `110 . . . 0`. The location where the
paging message is transmitted when this bitmap is used will be
described with reference to FIG. 14.
FIG. 14 is a diagram illustrating an example of a location where a
paging message is transmitted if paging indication bits of a
plurality of paging sub groups are transmitted at the same time
according to another embodiment of the present invention.
In FIG. 14, it is assumed that N paging sub groups (paging sub
group 1, paging sub group 2, . . . paging sub group N) exist. It is
also assumed that paging indication bits indicating whether the
paging message of each paging sub group is transmitted are
transmitted through the first subframe of each paging cycle.
If the paging indication bit is set to `110 . . . 0` in the first
subframe of the first paging cycle, it represents that only the
paging messages for the paging sub group 1 and the paging sub group
2 are transmitted. In this case, the subframe where the paging
message of the paging sub group having the paging indication bit
set to 1 is transmitted can be determined using a number of the
paging sub group (i.e., paging sub group ID). Namely, the paging
message of the paging sub group 1 can be transmitted from the ith
subframe of the subframes where the paging indication bit is
transmitted. Also, the paging message of the paging sub group 2 can
be transmitted from the i+8th subframe of the subframes where the
paging indication bit is transmitted.
If the paging indication bit is set to `11 . . . 1` as illustrated
in the second paging cycle of FIG. 14, in case of the paging sub
group N, the paging indication bit can be transmitted from the
i+8(N-1)th subframe of the subframes where the paging indication
bit is transmitted. In this case, the transmission intervals of the
paging message are spaced apart from each other by 8 subframes
whenever the paging sub group increases by 1. However, the
transmission intervals are only exemplary and may be modified if
necessary.
As described above, although the location where the paging message
of the paging indication bit is transmitted may be defined in
accordance with a previously determined rule, the location where
the paging message is transmitted may be defined through
predetermined signaling. For example, information of the location
where the paging message is transmitted can be transmitted together
with the paging indication bit.
2-2-2. Method for Setting a Paging Indication Bit
Hereinafter, a method for setting a paging indication bit in
accordance with various sizes and formats will be described.
2-2-2-1. 1 Bit Paging Indication Method
If a 1 bit paging indication method is used, whether a paging
message of one paging sub group is transmitted can be identified
per superframe. Accordingly, if the paging indication bit is
transmitted through any one of the locations described with
reference to FIG. 11, it is preferable that the paging indication
bit is transmitted through different superframes per paging sub
group. This will be described with reference to FIG. 15.
FIG. 15 is a diagram illustrating an example of a 1 bit paging
indication method in accordance with another embodiment of the
present invention.
Referring to FIG. 15, a paging indication bit of the paging sub
group 1 can be transmitted from the first superframe of the paging
cycle, and a paging indication bit of the paging sub group 2 can be
transmitted from the second superframe of the paging cycle. All
mobile stations belonging to each paging sub group can wake up to
receive the paging message only if the paging indication bit of the
paging sub group to which the mobile stations belong is set to 1.
It is preferable that the as any one of the locations described
with reference to FIG. 11 is designated as the location where the
paging indication bit is transmitted. Also, the location where the
paging indication bit is transmitted can be designated through one
of the methods described in 2-2-1.
2-2-2-2. n Bit Paging Indication Method
In this embodiment, paging intervals for receiving paging
indication (PI) in all mobile stations belonging to the same paging
group can be established equally. Also, in this embodiment, paging
information that includes paging cycle, paging offset, paging
interval length and paging sub group number can be broadcasted
through system information. This will be described with reference
to Table 7.
Table 7 illustrates an example that paging information related to
another embodiment of the present invention is broadcasted through
system information.
TABLE-US-00007 TABLE 7 Type Length Value Scope xxx x PAGING_CYCLE
RNG-RSPDREG- PAGING_OFFSETPaging CMDSystem Interval LengthPaging-
Information group-ID Paging sub (BCH) group number: the number of
paging sub groups belonging to paging group
Referring to Table 7, paging information transferred to the mobile
station through the ranging response message or the deregistration
command message in the general wireless communication system can be
included in the system information so that the information can be
transmitted to the mobile station through the BCH. Also, the paging
information can further include information of the number of paging
sub groups.
In this way, all mobile stations can identify the paging subframe
where paging indication (PI) is transmitted, through the
broadcasted paging information. Accordingly, each mobile station
belonging to each paging sub group can identify paging indication
of its paging sub group number, and can receive the paging message
through any one of the methods described in 2-2-1 if the paging
message of its paging sub group is transmitted.
Also, in this embodiment, paging indication (PI) indicating whether
the paging message of the mobile station belonging to each paging
sub group is transmitted can have an n-bit bitmap type. This will
be described with reference to FIG. 16.
FIG. 16 is a diagram illustrating a method for transmitting a
paging message using bitmap type paging indication in accordance
with another embodiment of the present invention.
In FIG. 16, it is assumed that N paging sub groups exist and N-bit
paging indication is transmitted to the mobile stations, which
belong to each paging sub group, through the first subframe of each
paging cycle. It is also assumed that the location where the paging
message of each paging sub group is designated through any one of
the methods described in 2-2-1.
In the first paging cycle, a paging indication bitmap of `10 . . .
0` indicating that the paging message of the paging sub group 1 is
only transmitted is transmitted to each paging sub group. As a
result, all mobile stations belonging to the paging sub group 1 can
receive the paging message by waking up in the previously
determined location.
In the second paging cycle, a paging indication bitmap of `010 . .
. 1` indicating that the paging messages of the paging sub group 2
and the paging sub group N are transmitted is transmitted to each
paging sub group. As a result, the mobile stations belonging to the
paging sub group 2 and the paging sub group N can receive the
paging message by waking up at the time when the paging message of
the corresponding paging sub group is transmitted.
2-2-2-3. Grouping Method of n Bit Paging Indication
According to the aforementioned n-bit bitmap paging indication
method using a bitmap of multi-bits, mobile stations belonging to
all paging sub groups of one paging group can identify paging
indication by waking up at the same paging interval. However, if
paging subframes where the paging indication using the multi-bit
bitmap is transmitted are also grouped, all the mobile stations of
the paging group may not wake up at the same time.
In this embodiment, N paging sub groups belonging to one paging
group can be divided into M paging indication groups. Namely,
mobile stations belonging to N/M paging sub groups can
simultaneously identify paging indication (PI) of N/M-bit size by
waking up at the same paging interval (listening interval). In this
case, N is divided by M when N is a multiple of M and the paging
sub groups are allocated to the paging indication group at the same
rate. However, the paging indication groups method can be used even
though the paging sub groups are not allocated to the paging
indication group at the same rate.
The mobile stations of each paging group can wake up at the paging
subframe determined per paging sub group to receive the paging
message only if paging indication of the paging sub groups to which
the mobile stations of each paging group belong is set. This will
be described with reference to FIG. 17.
FIG. 17 is a diagram illustrating an example that a paging
indication grouping method in accordance with another embodiment of
the present invention is used.
Referring to FIG. 17, one paging group is divided into four paging
sub groups, wherein the paging sub groups 1 and 2 are included in
the paging indication group 1 and the paging sub groups 3 and 4 are
included in the paging indication group 2. In this case, paging
indication of each paging indication group can be transmitted
through the first subframes of different superframes. The mobile
stations of the paging sub groups belonging to the same paging
indication group can be established to have the same paging
interval (or listening interval). Namely, supposing that the paging
sub groups 1 and 2 belong to the paging indication group 1 and the
paging sub groups 3 and 4 belong to the paging indication group 2,
the mobile stations of the idle mode, which belong to each paging
indication group, identify the same paging indication bit with the
same listening interval.
In this case, the paging interval or the listening interval could
be a superframe unit, and the mobile stations of the idle mode can
identify the paging indication bit at the SFH which corresponds to
a start part of the listening interval. Also, the mobile stations
of the idle mode can identify the paging indication bit and at the
same time receive system information transmitted through the SFH or
the subframe including SFH.
Furthermore, the mobile stations of the idle mode may identify the
paging indication bit through system information. The mobile
stations which have identified the paging indication bit can
receive the paging message by waking up at the paging subframe or
frame where the paging message of their paging sub group is
transmitted, only if the paging indication bit of the paging sub
group to which each mobile station of the idle mode belongs is
set.
For example, in the first paging cycle of FIG. 17, the paging
indication bit of the paging indication group 1 is set to 10
through the first subframe of the first superframe. All mobile
stations of the paging sub groups 1 and 2 receive the paging
indication bit, and identify whether the paging message is
transmitted to the paging sub group to which they belong. Since the
paging indication bit is set to 10, the mobile stations belonging
to the paging sub group 1 can receive the paging message at the
previously determined subframe, and the mobile stations belonging
to the paging sub group 2 continue to be operated in the idle
mode.
The mobile stations of the paging sub groups 3 and 4 belonging to
the paging indication group 2 can receive the paging indication bit
of the paging indication group 2 from the first subframe of the
second superframe of the first paging cycle. Since the paging
indication bit of the paging indication group 2 is set to 00, the
mobile stations belonging to the paging indication group 2 can
identify that the paging message is not transmitted, and can
continuously be operated in the idle mode.
In case of the second paging cycle, since the paging indication bit
of the paging indication group 2 is 01 in the first subframe, only
the mobile stations belonging to the paging sub group 2 can receive
the paging message at the previously determined paging subframe.
The mobile stations belonging to the paging sub groups 3 and 4 of
the paging indication group 2 can receive the paging indication bit
of the paging indication group 2 from the first subframe of the
second superframe of the first paging cycle. Since the paging
indication bit of the paging indication group 2 is set to 11, all
the mobile stations belonging to the paging indication group 2 can
receive the paging message from the paging subframe previously
established for each paging sub group.
FIG. 18 is a diagram illustrating another example that paging
indication grouping method in accordance with another embodiment of
the present invention is used.
As illustrated in FIG. 18, if four paging sub groups exist within
the paging group, the paging message of each paging sub group can
be allocated one by one in a frame unit within one superframe.
Namely, if the four paging sub groups belong to one paging
indication group, the paging message of each paging sub group can
be allocated either one by one in due order per frame or through
modulo operation.
2-2-2-4. Method for Transmitting a Paging Indication Bit Map
Through SSFH
In the IEEE 802.16m system, the SFH is divided into a primary
superframe header (PSFH) and a secondary superframe header (SSFH).
Although the PSFH is transmitted per superframe, the SSFH may not
be transmitted per superframe. Information transmitted through the
SSFH is divided into different sub-packets and then can be included
in the SSFH. According to this embodiment, a method for
transmitting a paging indicator having a similar function to that
of the aforementioned paging indication bit through S-SFH SP5 IE
(Paging Sub-Packet IE) that can be used to transfer paging
information will be disclosed.
Hereinafter, contents that can be included in the S-SFH SP5 IE will
be described with reference to Table 8 to Table 10. In Table 8 to
Table 10, it is assumed that four paging sub groups exist per
paging group.
First of all, Table 8 illustrates an example of contents that can
be included in the S-SFH SP5 IE in accordance with another
embodiment of the present invention.
TABLE-US-00008 TABLE 8 Syntax Size (bit) Notes S-SFH SP5 IE format
( ) { N_PGID 3 Number of PGIDs in the sub-packets PGID List 16 *
N_PGID List of Paging group IDs For (i=0;i<N_PGID; i++){ Paging
group ID TBD Paging indicator 4 } }
Referring to Table 8, since four paging sub groups are included in
one paging ID, a paging indicator field is established to have a
size of four bits.
Table 9 illustrates another example of contents that can be
included in the S-SFH SP5 IE in accordance with another embodiment
of the present invention.
TABLE-US-00009 TABLE 9 Syntax Size (bit) Notes S-SFH SP5 IE format
( ) { N_PGID 3 Number of PGIDs in the sub-packets Paging Indicator
Usage 1 0b = 1 Paging indicator Flag bitmap is present0b = 0 paging
indicator bitmap is absent PGID List 16 * N_PGID List of Paging
group IDs If( Paging Indicator Usage Flag ==1) { For
(i=0;i<N_PGID; i++){ Paging group ID TBD Paging indicator 4 } }
}
Referring to Table 9, a Paging Indicator Usage Flag field is set to
0 when the paging messages of all paging groups transmitted within
the corresponding superframe are not transmitted at all.
Table 10 illustrates other example of contents that can be included
in the S-SFH SP5 IE in accordance with another embodiment of the
present invention.
TABLE-US-00010 TABLE 10 Syntax Size (bit) Notes S-SFH SP5 IE format
( ) { N_PGID 3 Number of PGIDs in the sub-packets PGID List 16 *
N_PGID List of Paging group IDs For (i=0; i<N_PGID; i++){ Paging
Indicator Usage Flag 1 0b = 1 Paging indicator bitmap is present0b
= 0 paging indicator bitmap is absent If( Paging Indicator Usage
Flag ==1) { Paging group ID TBD Paging indicator 4 } } }
Referring to Table 10, unlike Table 9, a paging indicator usage
flag can respectively be applied to each paging group instead of
all paging groups transmitted within the corresponding
superframe.
3. Method for Detecting a Paging Message Using Paging CID
According to still another embodiment, a method for detecting a
paging message using paging CID is disclosed, in which decoding
overhead of a mobile station can be reduced and the mobile station
can detect the paging message more quickly.
In the general wireless communication system, broadcast CID is used
to transmit the paging message. However, in this embodiment, a
method for transmitting a paging message using paging CID dedicated
for the paging message is suggested. In this case, even if one CRC
is attached to all sub-maps and the mobile station should perform
blind decoding, mobile stations of an idle mode and mobile stations
of a normal mode can be operated effectively. Namely, only the
mobile stations of the idle mode can receive the message
transmitted using the paging CID while the mobile stations of the
normal mode do not receive the message transmitted using the paging
CID. Accordingly, overall system throughput can be improved and
power consumption of the mobile station can be reduced.
Meanwhile, if a blind decoding scheme is used, in this embodiment,
a method for transmitting control signaling for a paging message in
a fixed location (for example, first location) of a sub-map can be
used. Namely, the paging message can be transmitted from a paging
subframe using a format of a fixed size in a fixed location of a
sub-map. Accordingly, it is possible to reduce decoding overhead
that may occur as the mobile station performs blind decoding for
all sub-maps to detect control signaling. If the mobile station
fails to perform blind decoding for control signaling of a
previously set size in a fixed location, it can be determined that
there is no paging message in the corresponding paging subframe.
Accordingly, the mobile station can enter the idle mode directly
without blind decoding for the other sub-map.
Accordingly, in this method, since the mobile station of the idle
mode decodes only a part which includes control information of the
paging message from the sub-map of the paging subframe, it is
effective in saving the power of the mobile station. This will be
described with reference to FIG. 19.
FIG. 19 is a diagram illustrating an example of a location where
control signaling for a paging message in accordance with another
embodiment of the present invention is transmitted.
Referring to FIG. 19, supposing that the fourth subframe is a
paging subframe, control signaling of the paging message can be
transmitted to the mobile station through a sub-map of the
corresponding subframe and is preferably located at the foremost
part of the sub-map. In this case, it is efficient in that the
mobile station can determine the presence of the paging message by
decoding only the foremost part of the sub-map of the paging
subframe.
4. Multi-Level Paging Cycle
According to a further embodiment, there is provided a method for
establishing a paging cycle (PAGING_CYCLE) value in a multi-level,
wherein the paging cycle value is one of parameters related to
paging that can be set between the mobile station and the base
station.
In case of the mobile station which is not paged for a long time,
power consumption and paging overhead can be reduced if the paging
cycle of the mobile station increases to a maximum value, which is
previously established, through a predetermined level. This will be
described with reference to FIG. 20.
FIG. 20 is a diagram illustrating an example that a paging cycle of
a mobile station is established in a multi-level in accordance with
the further embodiment of the present invention.
First of all, as illustrated in FIG. 20(a), the paging cycle of the
mobile station is classified into three levels. If the mobile
station is not paged for a time corresponding to one level, a time
equivalent to twice of a previous level can be established as a
paging cycle of next level. At this time, it is assumed that the
paging cycle of the first level is 100 ms and the maximum paging
cycle is 400 ms corresponding to the third level.
If the mobile station is not paged for the paging interval of the
first paging cycle of 100 ms after entering the idle mode, the
mobile station performs the operation of the idle mode in a paging
cycle of 200 ms of the second level. If the mobile station is not
paged for the paging interval even by the paging cycle of the
second level, the mobile station performs the operation of the idle
mode in a paging cycle of 400 ms of the third level. If the mobile
station is not paged for the paging interval even by the paging
cycle of the third level, the mobile station performs the operation
of the idle mode in a state that the paging cycle of the third
level corresponding to the maximum paging cycle is maintained.
Next, if the mobile station is not paged for the twice-repetition
interval of the paging cycle of one level as illustrated in FIG.
20(b), the mobile station can be operated in accordance with the
paging cycle of next level. Of course, the number of repetition
times can be changed in accordance with user s requirements or
system status until the paging cycle of one level is converted to
that of next level.
The maximum value of the aforementioned paging cycle can be
transmitted to the mobile station in a type illustrated in Table
11.
Table 11 illustrates an example of contents included in a message
notifying the mobile station of the maximum paging cycle of the
multi-level paging cycle in accordance with the further embodiment
of the present invention.
TABLE-US-00011 TABLE 11 Type Length Value Scope Xxx x PAGING_CYCLE
MAX RNG-RSPDREG-CMD PAGING_CYCLE: Maximum value of (System
Information) D PAGING_CYCLEPAGING_OFFSETPaging Interval
LengthPaging-group-ID
Referring to Table 11, the maximum paging cycle (MAX PAGING_CYCLE)
value can be added to the paging information that can be used in
the general wireless communication system. In this case, it is
preferable that the maximum paging cycle value is equal to or
greater than a paging cycle (PAGING_CYCLE) parameter value.
Although the paging information may be transmitted to the mobile
station through the ranging response message or the deregistration
command message, the paging information may be broadcasted through
system information as described in 2-2-2-2.
In this embodiment, the paging cycle increases by a predetermined
rate or predetermined value if a paging cycle of a rule previously
agreed between the mobile station and the base station, for
example, a given time or a given number of times, passes. If the
paging cycle reaches the maximum value, the maximum value can be
maintained. Also, an increase value and an increase condition of
the paging cycle may be established explicitly through a message
unicasted between the mobile station and the base station.
As a still further embodiment of the present invention, the mobile
station and the base station through which the embodiments of the
present invention can be performed will be described with reference
to FIG. 5 to FIG. 20.
The mobile station can be operated as a transmitter in the uplink,
and can be operated as a receiver in the downlink. Also, the base
station can be operated as a receiver in the uplink, and can be
operated as a transmitter in the downlink. Namely, the mobile
station and the base station can include a transmitter and a
receiver to transmit information or data.
The transmitter and the receiver can include processor, module,
part, and/or means for performing the embodiments of the present
invention. Particularly, the transmitter and the receiver can
include a module (means) for encoding a message, a module for
decoding the encoded message, and an antenna for transmitting and
receiving the message.
The mobile station used in the embodiments of the present invention
can include a low power radio frequency (RF)/intermediate frequency
(IF) module. Also, the mobile station can include a means, module
or part for performing controller function, medium access control
(MAC) frame variable control function according to service
characteristics and radio wave condition, handover function,
authentication and encryption function, packet modulation and
demodulation function for data transmission, quick packet channel
coding function, and real-time modem control function, thereby
performing the aforementioned embodiments of the present
invention.
The base station can transmit data received from an upper layer to
the mobile station by wireless or wire. The base station can
include a low power RF/IF module. Also, the base station can
include a means, module or part for performing controller function,
orthogonal frequency division multiple access (OFDMA) packet
scheduling, time division duplex (TDD) packet scheduling and
channel multiplexing function, medium access control (MAC) frame
variable control function according to service characteristics and
radio wave condition, handover function, authentication and
encryption function, packet modulation and demodulation function
for data transmission, quick packet channel coding function, and
real-time modem control function, thereby performing the
aforementioned embodiments of the present invention.
It will be apparent to those skilled in the art that the present
invention can be embodied in other specific forms without departing
from the spirit and essential characteristics of the invention.
Thus, the above embodiments are to be considered in all respects as
illustrative and not restrictive. The scope of the invention should
be determined by reasonable interpretation of the appended claims
and all change which comes within the equivalent scope of the
invention are included in the scope of the invention.
INDUSTRIAL APPLICABILITY
The embodiments of the present invention can be applied to various
wireless access systems. Examples of various wireless access
systems include 3GPP (3rd Generation Partnership Project) system,
3GPP2 system and/or IEEE 802.xx (Institute of Electrical and
Electronic Engineers 802) system. The embodiments of the present
invention can be applied to all technical fields to which the
various access systems are applied, as well as the various access
systems.
* * * * *